Yes, eventually. And I only recognize it because I have done it. You can cut off that part. A few more things, I think you need more mulch. If you have clay (as I do as well), you want to make sure the soil is covered well so it doesn't dry out. Keep watering it and don't worry about RRD, it's not in California as far as I know. Once the weather cools off a bit, the rose should look better.

I see leaves with white spots that might be from Sawfly Larvea (Rose Slugs). RS are green worm looking things that range in size from tiny up to a inch long. Usually found on the underside of leaves...They eat holes in leaves also... They can be picked off the bush OR least toxic spray would be safers insect killing soap... But since you have yellowing leaves I'd hold off spraying it with anything until you get your problem figured out... Blackspots might be what we call blackspot or a similar fungus disease... Not sure why leaves are yellowing...? Many things can cause leaves to yellow... https://www.gardeningknowhow.com/ornamental/flowers/roses/yellow-rose-leaves.htm

Tea roses (not Hybrid Tea) are warm climate roses that love California and the Southeast. They are mainly sold online from specialty nurseries. Your northeast area has several great gardeners who contribute here. Teas can grow in some cooler winter areas but it is more of a challenge. Picking roses that love your area is an art. Paying attention to the location of the posters really helps. HMF roses can also help with details, photos and comments on an individual rose from different area's contributors. I took a chance here on Tea roses, because I had never grown them in my previous cold gardening areas. I got inspired by Ingrid, but it was a gamble I thought, because I am not in California. I am 30 miles from the N California border. Some of my ramblers are getting cooked here, and I did have a baby gallica "Rush Family" not bloom this Spring. This may be too hot for them. A lot is trial and error. I also now ordered more regular lilacs and this also might be on the edge of too warm here. I do have 3 lilacs doing well here, so I thought I would take a chance. In your case Hybrid Teas could work well but black spot resistance would be important. Good luck, three boxer lover.

@sharon2079 @joeywyomingzone4 Thanks guys, I was also thinking it looks like symptoms after watering too much and roots rot. but the soil looks wet because the photo was taken just after watering, before that, the plants was transplanted and watered 8 days ago, and during these 8 days, they got no watering, so I don't think the soil is too wet(during these days)?(considering the pots are not large, 8 days should be long enough for water to dry out?) Before watering I poke my fingers into the soil and at least the top 3 cm soil are totally dry.... @sautesmom Sacramento I know this brand, but most foreign plant brands are doing their business in China by using Chinese agencies, so not many people in China know Monrovia. @K S 7b Little Rock (formerly of Seattle) place for plants in China is very limited(especially in big cities), most people grow rose in balcony and we only use small pots...